1. Field of the Invention
The present invention relates to an endoscope apparatus comprising a control portion constructed using programmable integrated circuits, the circuit function of each which can be changed.
2. Description of the Related Art
Recently, endoscopes have been widely used in the medical and industrial fields. The endoscope is used in a case where a biopsy or a curing treatment is performed by using a treatment tool as well as to observe or inspect the inside portion of an organism.
Therefore, the endoscope is combined with peripheral units for use in performing observation and treatment, such as a light source unit for supplying irradiation light for observing a subject which is substantially a necessary peripheral unit, an external camera unit for picking up an image, and an electric knife for performing excision.
The foregoing peripheral unit usually consists of the body of the peripheral unit and a control unit to which the body of the peripheral unit is connected, which drives and controls the body of the peripheral unit and which processes signals.
The products of the foregoing peripheral units to be used while being combined with the endoscope are usually in a state where their bodies have different structures and different functions. Therefore, they are usually designed by different designers, and usually different elements are employed. Furthermore, the control units for use together with the bodies of the peripheral units are usually designed by different designers or comprise different elements.
Therefore, if the control units control similar operations, the fact that the control units are designed individually (independently) increases the number of processes for designing the control unit. Thus, there arises a problem in that the cost of the product cannot be reduced. Furthermore, the necessity of disposing similar control circuits for respective peripheral units raises a problem that the size of the apparatus cannot be reduced. When a plurality of peripheral units are used in a combined manner, circuits having functions that are not always required are sometimes undesirably disposed.
Many types of endoscopes and peripheral units, such as light source units and video processors, may form the endoscope apparatus. A consideration will be made about a combination of, for example, an endoscope, a video processor and a light source unit. Endoscopes are arranged to have different outer diameters to be adaptable to the portion for use, such as the upper digestive tube or the lower digestive tube. Also the available video processors have different characteristics. In a case where the different types of endoscopes are used, the characteristics, such as the response speed of the automatic light adjustment function realized when the endoscope and the peripheral units are combined, are changed. Therefore, there is a need for preparing a multiplicity of light source units having different characteristics to be adaptable to the several types of endoscopes and video processors in order to obtain adequate operational characteristics. In this case, a problem of cost reduction arises. In a case where a common light source unit is used when several types of endoscopes and video processors are used, desired characteristics for the endoscope apparatus sometimes cannot be obtained. For example, a desired response speed cannot be realized because the response speed of the automatic light adjustment means is lowered depending upon the combination.
The peripheral unit to be used in combination with the endoscope is designed and adjusted before it is supplied as a product in such a manner that the characteristics of the unit, for example, the characteristics of a light quantity adjustment means of a light source unit, are set to realize the optimum conditions in a state of normal use.
As an example, in an automatic light adjustment means of an endoscope apparatus the light quantity adjustment for observation is performed by a light adjustment means for adjusting the aperture ratio of a diaphragm disposed in an optical path of the light source unit in accordance with the brightness of a subject image obtained through an image pickup means. The loop gain, the response speed and the adjustable range of the automatic light adjustment means are set to be adaptable to a state of normal use. Although portion for controlling each function of the light source unit is formed by using a digital circuit, the circuit function, and the operational characteristics of the control portion have been determined by a fixed circuit structure corresponding to the set value of the operation of each function.
Since the operational characteristics of the unit cannot easily always be set to the optimum state, the optimum setting for a user is not always realized. In this case, the user must adjust the unit to be adaptable to the state of use or to satisfy the desire of the user.
Since the conventional apparatus has been arranged such that the operational characteristics of the apparatus are fixedly set to be adaptable to the state of normal use and they cannot freely be set to be adaptable to other states of use, a problem sometimes arises in that the characteristics, the functions, values of the operational state, the operational characteristics, the adjustable range of each function, and the adjustment steps that are not suitable for the user are set. In addition, there arises a need to perform adjustment or resetting to be adaptable to the state of use or to satisfy the desire of a user. That is, the operational characteristics of the apparatus cannot freely be set to satisfy the desire of a user, to be adaptable to the state of use and the combination of units. Thus, a problem rises in that the apparatus cannot always be used in an optimum state.